Method isPartition

FindThePunishmentNumberOfAnInteger.java:3–16

(int j, String i2, int i, int curSum)

//plain recursion
class Solution {
    public boolean isPartition(int j, String i2, int i, int curSum){
        int n = i2.length();
        // base case
        if(j == n){
            return (curSum == i);
        }
        for(int index=j;index<n;index++){
            int val = Integer.parseInt(i2.substring(j,index+1));
            if(isPartition(index+1,i2,i,curSum+val)){
                return true;
            }
        }
        return false;
    }
    public int punishmentNumber(int n) {
        int res=0;
        for(int i=1;i<=n;i++){